Lesson objective: Practice transforming figures in the coordinate plane.

This lesson helps to build procedural skill with completing a sequence of transformations in the coordinate plane. Trapezoids in the coordinate plane are used here because the different base lengths make it easier to see positional and orientational changes. This work develops students' understanding that the structure of the coordinate plane allows us to describe geometric transformations using coordinates.

Students engage in Mathematical Practice 7 (make use of structure) as they use features of the coordinate plane to describe and perform transformations. The task also requires students to use all three types of rigid transformations to encourage full understanding of each type. In the in-class practice, students play a game in which they use transformations to gradually change to a desired location of the game board (a coordinate plane).

**Key vocabulary:**

- center of rotation
- line of reflection
- reflect
- rotate
- translate

**Special materials needed:**

- patty paper (optional)
- transparency and wet or dry-erase markers (an optional alternative to patty paper)